I would like to hear your opinion on the significance/role of CCAAT boxes in
In yeast (both S. cereviseae and S. pombe) the CCAAT box (and factors that
bind to it) is involved in regulating a large number of nuclear genes that
are involved in mitochondrial biogenesis and as such plays an important role
in carbon source control.
In mammalian cells there are distinct classes of CCAAT boxes, with distinct
flanking elenments and these are located proximal to the TATA box ((-70 to
-80) rather than distal (-300 to -500) as in yeast. In mammalian cells
CCAAT boxes mostly act as constitutive activators in combination with other,
highly regulated activators.
Potential CCAAT boxes have been reported for a variety of plant genes
including NADH dependent hydroxypyruvate reductase from cucumber, gliadin -
an endosperm specific storage protein from Triticum aestivum, an actin gene
from volvox, the nopaline synthase promoter, bronze allele promoter from
maize and PEP carboxylase from Flaveria.
This is a mixed batch. Undoubtedly there are many more identified and
unidentified potential CCAAT boxes in plant promoters.
I would appreciate hearing anyones thoughts on the significance of CCAAT
boxes in plant promoters. Is there any similarity with the role in yeast or
mammalian cells? Is there no similarity, with only the box being conserved
and the regulatory role being altered over evolution? Also if your favourite
gene contains a CCAAT box I would like to know about it.
I will summarise replies to the net.
Thanks for your time,
Ian GrahamIan Graham
Carnegie Institution of Washington
Dept of Plant Biology
290 Panama Street
Tel 0101 415 325 1521
Fax 0101 415 325 6857
(until 30 Sept, 1994, then:
Dept Biochemistry, University Glasgow,
Glasgow G12 8QQ. UK).